function somenteNumeros(dom){
	var permitidos = '0123456789';
	//var key = e.keyCode;
    //var chr= String.fromCharCode(key);
	
	for (i = 0; i < dom.value.length; i = i + 1){
		if (permitidos.indexOf(dom.value[i]) == -1){
			while (dom.value.indexOf(dom.value[i]) != -1)
				dom.value=dom.value.replace(dom.value[i],'');
		}
	}
}